drm/radeon: allow userptr write access under certain conditions

It needs to be anonymous memory (no file mappings)
and we are requried to install an MMU notifier.

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/radeon/radeon_gem.c b/drivers/gpu/drm/radeon/radeon_gem.c
index 2a6fbf1..01b5894 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_gem.c
+++ b/drivers/gpu/drm/radeon/radeon_gem.c
@@ -285,19 +285,24 @@ int radeon_gem_userptr_ioctl(struct drm_device *dev, void *data,
        if (offset_in_page(args->addr | args->size))
                return -EINVAL;
 
-       /* we only support read only mappings for now */
-       if (!(args->flags & RADEON_GEM_USERPTR_READONLY))
-               return -EACCES;
-
        /* reject unknown flag values */
        if (args->flags & ~(RADEON_GEM_USERPTR_READONLY |
            RADEON_GEM_USERPTR_ANONONLY | RADEON_GEM_USERPTR_VALIDATE |
            RADEON_GEM_USERPTR_REGISTER))
                return -EINVAL;
 
-       /* readonly pages not tested on older hardware */
-       if (rdev->family < CHIP_R600)
-               return -EINVAL;
+       if (args->flags & RADEON_GEM_USERPTR_READONLY) {
+               /* readonly pages not tested on older hardware */
+               if (rdev->family < CHIP_R600)
+                       return -EINVAL;
+
+       } else if (!(args->flags & RADEON_GEM_USERPTR_ANONONLY) ||
+                  !(args->flags & RADEON_GEM_USERPTR_REGISTER)) {
+
+               /* if we want to write to it we must require anonymous
+                  memory and install a MMU notifier */
+               return -EACCES;
+       }
 
        down_read(&rdev->exclusive_lock);